Need a 20-25 w or better amp desing

[cepa]

Hey guys, i need an amp circuit (HUGE BONUS IF IT HAS A PCB), prefferably using the TDA2030 chip which can delliver 20-25w or more into a 4 ohm speaker at 12 DC(i will be running this thing of a 12v battery)

[Bone]

You'll only get about 3-4 watts in 4 ohms, off a 12 volt battery with this chip. To get 20 watts you will need a 30 volt supply! Or +15v and -15v. Check the datasheet!

[pacificblue]

A BTL amp can deliver around 16 W into 4 Ohm from a single 12 V supply. Look for car amp ICs that advertise themselves as 20-25 W amps. They usually are BTL configured. E.g. TDA7374, TDA7393, etc.

[sregor]

Only chipamp I have heard of which will give out more power with 12 volts without a switching supply is TDA1562Q. It is a bridged, class H design which gets the extra voltage swing by pumping up a cap (kinda like a switching supply). I've only read the sheet - haven't seen any kits around, but haven't seriously looked. Most serious battery users use class D - much longer battery life. Good luck with it.

[fooboo]

Hi there

Try this link. I am nearly ready to build a pair. Then I'm going to try and build one of the 'real' chip-amps =)

Silicon Chip Online - The "Mighty Midget" Audio Amplifier Module

regards

Fooboo

[!]

^ I'd imagine cepa has already finished the amp or gave up on it since the topic is over 9 months old.

[nigelwright7557]

There are laods of lm3886 amps on ebay.
You can buy ready built, kit form or just the pcb.
Spoiled for choice !

[johnr66]

Originally Posted by pacificblue

A BTL amp can deliver around 16 W into 4 Ohm from a single 12 V supply. Look for car amp ICs that advertise themselves as 20-25 W amps. They usually are BTL configured. E.g. TDA7374, TDA7393, etc.

That is usually an inflated rating at 10% distortion. If you run the ICs at 15 volts you can usually get 16 watts just before clipping. At 12 volts, don't expect anything much better than 10 watts of clean power into 4 ohms.

[PRR]

>> A BTL amp can deliver around 16 W into 4 Ohm from a single 12 V supply
> That is usually an inflated rating at 10% distortion

It's not too bogus.

In cars, "12V" is more like 12.6V engine off, and engine-on is often taken as 14.4V or 13.6V.... small diff, but significant if you are sanity-checking.

The claim, "16W in 4 ohms" implies 8V RMS or 22.63V peak to peak. In BTL that is 11.3Vp-p from each side.

Car-chips are designed for minimum voltage loss. Part of the differences is how far they go to get lower drop. The better ones easily pull-down to less than 0.3V. Pull-up with simple techniques leads to 1.0V drop. Bootstrapping can get to 0.4V pull-up loss.

13.6V-0.3V-0.4V = 12.9V peak-peak swing.
12.6V-0.3V-0.4V = 11.9V peak-peak swing.

We need 11.3Vp-p.

It works out.

Taking nominal 14.4V, a "23W" rating may be un-clipped.

[johnr66]

I know the math works, but in practice, with a regulated 14 volt supply, I can't do better than 13 or 14 watts RMS max continuous sine wave into a non inductive 4 ohm load with these ICs. I've tried a few.

Which ICs are showing pre clipping (low distortion) at 23 watts into 4 Ohm loads with 14.4 Vs? All the IC's I'm aware of show 22-24 watts at 10% distortion. I'm talking normal BTL ICs, not the ones with charge pumps.